Cooling system, in particular of a motor vehicle

ABSTRACT

The invention concerns a cooling system, in particular a motor vehicle cooling system comprising
         a cooling circuit, in which a cooling medium is circulated by means of a cooling medium pump; wherein   the cooling medium pump or another work machine is driven by means of a drive machine via a hydrodynamic coupling, comprising a pump impeller driven by the drive machine and a turbine wheel driving the cooling medium pump, which together form a toroidal working chamber which can optionally be filled with working medium; wherein   the working medium is the cooling medium;   a compensating container, comprising a space filled with cooling medium and an air chamber above a cooling medium level in the space filled with cooling medium.       

     The invention is characterised in that the working chamber of the hydrodynamic coupling is always connected to the air chamber or can optionally be connected to the latter via an air-conducting connection.

The present invention concerns a cooling system, having the characteristics detailed in the preamble of the claim 1.

Cooling systems of the present type are used for cooling a drive motor and/or other units, in particular of a vehicle drive train. They include a cooling system, in which a cooling medium is circulated by means of a cooling medium pump. The cooling medium is for instance water or a water mixture. The circulation in the cooling circuit feeds the cooling medium to the unit to be cooled, in particular to a drive motor, which cooling medium absorbs the heat to be discharged and flows further towards a heat exchanger provided in the cooling system, in particular a water-air-heat exchanger, where it releases the absorbed heat to the surrounding atmosphere. As a matter of principle, the heat absorbed by the cooling medium cannot be discharged to the surrounding atmosphere simply either, but rather be used profitably in the drive train respective in the vehicle or recovered as power. The present invention can be used with every cooling system of the type aforementioned.

While previously the cooling medium pump in a motor vehicle cooling system was in steady drive connection to the drive motor of the vehicle and hence was driven according to the rotation speed of the drive motor, cooling medium pumps driven by means of an electric motor have been suggested recently, or such pumps, with which a switchable magnetic coupling is arranged in the drive connection between the drive motor and the cooling medium pump. Moreover, the German patent application 10 2008 0034 973.9, not yet published, suggests coupling the rotor of the cooling medium pump in a torque-proof manner to the secondary wheel of the hydrodynamic coupling and using simultaneously the cooling medium as a working medium of the hydrodynamic coupling.

Although the last-mentioned form of embodiment enables an adjustment of the power input of the cooling medium pump to the cooling efficiency currently required in the vehicle and offers fuel savings, and besides due to the fact that the working medium of the hydrodynamic coupling is the cooling medium of the cooling system at the same time and due to the fact that the warm-up phase can be shortened by reducing the cooling efficiency of the cooling medium pump in the case of cold start of the drive machine, problems could be observed when using conventional hydrodynamic couplings in the drive train between the drive machine and the cooling medium pump when emptying the working chamber of the hydrodynamic coupling, to switch off the cooling medium pump partially or completely. So the working medium was not always evacuated from the working chamber of the hydrodynamic coupling to the desired extent since the cooling system is generally designed as a system sealed to the surrounding atmosphere, in which overpressure can occur.

The object of the present invention is to further develop a cooling system of the type above mentioned in such a way that the working chamber of the hydrodynamic coupling is always emptied to the desired extent.

The object of the invention is solved by a cooling system exhibiting the features of claim 1. Particularly advantageous embodiments of the invention are disclosed in the dependent claims.

The cooling system according to the invention, in particular in the form of a motor vehicle cooling system, includes a cooling system, in which a cooling medium is circulated by means of a cooling medium pump. The cooling medium pump is driven by means of a drive machine via a hydrodynamic coupling, which is in particular the drive machine for driving the motor vehicle at the same time. Alternately or additionally, it is also possible according to the invention to drive another working machine than the cooling medium pump via a corresponding hydrodynamic coupling and hence to achieve reliable emptying of the working chamber of the hydrodynamic coupling by means of the embodiment according to the invention, which is described in more detail below, so as to reduce the rotation speed of the secondary wheel of the hydrodynamic coupling, in particular to stop the secondary wheel of the hydrodynamic coupling.

According to the invention, the working medium of the hydrodynamic coupling is the cooling medium of the cooling system at the same time. Moreover, a compensating container is provided which comprises a space filled with cooling medium and an air chamber above a cooling medium level in the space filled with cooling medium. According to the pressure in the cooling system or according to the temperature of the cooling medium in the whole cooling system, the cooling medium level in the compensating container will rise or fall and the air chamber above the cooling medium level will decrease or increase accordingly.

According to the invention, the working chamber of the hydrodynamic coupling is always connected to the air chamber in the compensating container via an air-conducting connection or can be connected optionally to the air chamber in the compensating container. It is thus possible that the “air cushion”, that is to say air from the air chamber of the compensating container, if desirable, flows into the working chamber of the hydrodynamic coupling and replaces the working medium flowing out of the working chamber of the hydrodynamic coupling. With working medium increasingly flowing out of the working chamber and hence with reduced filling level of the working chamber, the slippage between the pump impeller and the turbine wheel of the hydrodynamic coupling increases and hence the slippage between the velocity of the drive machine and the work machine driven via the hydrodynamic coupling, in particular of the cooling medium pump increases.

In particular, the cooling system is designed as a pressure-tight sealed system to the surrounding atmosphere, in which overpressure prevails with respect to the surrounding atmosphere, permanently or according to certain constraints, for instance the temperature of the cooling medium.

The air-conducting connection, via which the working chamber is connected to the air chamber in the compensating container, includes according to an embodiment of the invention a shut-off valve, in particular in the form of a directional valve, for instance a directional control valve, in order to interrupt and release said air-conducting connection selectively.

According to an advantageous embodiment of the invention, the working chamber of the hydrodynamic coupling is always connected to the suction side of the cooling medium pump or can optionally be connected to the latter via an additional connection for conveying the working medium. If a connection for conveying the working medium is provided, which can be connected optionally, said connection may include a valve, in particular a distributing valve, to release the connection in a first switching mode and to interrupt it in a second switching mode.

Additionally or alternately, the working chamber of the hydrodynamic coupling can optionally be connected to the pressure side of the cooling medium pump via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve, for instance a directional valve, to switch off the hydrodynamic coupling or to increase the slip of the hydrodynamic coupling by partial emptying of the working chamber.

Alternately or additionally the working chamber of the hydrodynamic coupling can moreover optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can then also optionally be interrupted, in particular by means of a valve, for instance a directional valve.

According to an advantageously embodiment, which can have one or several of previously described connections for conveying the working medium, the working chamber of the hydrodynamic coupling has an inlet and an outlet, whereas at least said inlet can be shut off in particular by means of a valve, for instance a directional valve, and the outlet is connected to the inlet via a connection for conveying the working medium, so that working medium discharged from the working chamber via the outlet is conveyed back to the working chamber at least partially via the inlet, naturally providing that the inlet is not shut off.

The valve provided in the air-conducting connection and/or the valve provided in one of the connections for conveying the working medium, described previously, can be actuated in a clocked manner so as to adjust the filling level of the working chamber with working medium variably and including partial fill-ups. Such an adjustment possibility means that the working chamber cannot only be filled and emptied simply but rather further different filling level are adjustable between a minimum filling level and a maximum filling level. Additionally or alternately, pressure regulating valves can be implemented so as to vary the filling level by throttling the flow of working medium more or less strongly into and/or out the working chamber. An on/off valve for instance can be arranged in the inlet to the hydrodynamic coupling as well as a control valve or regulating valve in the outlet of the hydrodynamic coupling.

The outlet of the hydrodynamic coupling can be connected with such a distance from the radially external periphery of the working chamber so that a residual amount of working medium always remains in the working chamber.

The valve provided in the air-conducting connection and the valve provided in at least one of the connections for conveying the working medium, described previously, can be combined to form a common valve, in particular a directional valve having a corresponding number of ports.

The turbine wheel of the hydrodynamic coupling can be designed integrally with a rotor of the cooling medium pump and/or can carry the rotor of the cooling medium pump.

The invention will now be described using exemplary embodiments.

Wherein

FIG. 1 is a schematic illustration of a first exemplary embodiment;

FIG. 2 is a schematic illustration of a second exemplary embodiment;

FIG. 3 is a schematic illustration of a third exemplary embodiment;

FIG. 4 is a schematic illustration of a fourth exemplary embodiment;

FIG. 5 is a schematic illustration of a fifth exemplary embodiment;

FIG. 6 is a schematic illustration of a sixth exemplary embodiment.

In all illustrations of FIGS. 1 to 6, the cooling system is represented schematically with a cooling circuit 1 in which the cooling medium pump 2 is driven by the drive machine 3 via a hydrodynamic coupling 4, whereas the turbine wheel 5 of the hydrodynamic coupling 4, which is driven hydrodynamically by a system flow of working medium in the working chamber 6 through the pump impeller 19, is designed as a single part with a rotor of the cooling medium pump 2. The drive machine 3 is cooled by means of the cooling medium and the heat is discharged out of the cooling medium by means of the heat exchanger 20 to the surrounding atmosphere. The cooling medium is the working medium of the hydrodynamic coupling 4.

The cooling medium pump 2 pumps the cooling medium from a suction side 21 to a pressure side 22. According to the embodiments in FIGS. 1 to 4, a compensating container 7 is connected to the suction side 21 for conducting the cooling medium and/or the working medium. According to the embodiments in FIGS. 5 and 6 conversely, the compensating container 7 is connected to the pressure side 22 for conducting the working medium. This type of port is not mandatory and could be replaced accordingly also alternately. Other connection points could further be considered.

The compensating container 7 has an air chamber 9 and a space 8 filled with cooling medium, as is illustrated by the symbol for a cooling medium level. In this instance, an overpressure valve is moreover indicated on the compensating container 7 in the region of the air chamber 9.

In all illustrated embodiments, the air chamber 9 is always or can optionally be connected to the working chamber 6 of the hydrodynamic coupling 4 via an air-conducting connection 10. In the embodiment according to FIG. 1, a permanent connection is for example provided wherein, as indicated by the dotted lines, a valve 11 could be provided for shutting off the air-conducting connection 10. The same goes for FIG. 2.

In the embodiment according to FIGS. 3 to 6 conversely, a 2/2-way valve (FIG. 4) or a 3/2-way valve (FIGS. 3, 5, 6) is provided in the air-conducting connection 10, the latter used to connect the working chamber 6 of the hydrodynamic coupling 4 optionally with the air in the compensating container 7 or to the cooling medium in the compensating container 7 or the suction side 21 of the cooling medium pump 2. Although not disclosed, a connection to the pressure side 22 of the cooling medium pump 2 would also be possible alternately, for instance instead of the indirect connection to the pressure side 22 via the compensating container 7 according to FIG. 5.

All the valves, which are used for shutting off the air-conducting connection 10 in the illustrated exemplary embodiments, are designated by the reference sign 11. When they are additionally used for interrupting a connection for conducting the working medium, said valves are designated by a further reference sign, according to whether they are arranged in a connection 12 of the suction side 21 of the cooling medium pump 2, for conducting the working medium to the working chamber 6—they are then designated additionally by the reference sign 23 (see FIGS. 3 and 6)—or whether arranged in a connection 14 of the space 8 filled with cooling medium of the compensating container 7, for conducting the working medium to the working chamber 6—then designated by the reference sign 18 (see FIG. 5).

In each of the illustrated examples of embodiments, the working chamber 6 of the hydrodynamic coupling 4 has an inlet 15 and an outlet 16. The outlet 16 is used for discharging working medium from the working chamber 6 when operating the hydrodynamic coupling 4 for driving the cooling medium pump 2 and/or when emptying the working chamber 6 for increasing the slip between the pump impeller 19 and the turbine wheel 5 or when switching off the hydrodynamic coupling 4. The inlet 15 is used accordingly for supplying working medium into the working chamber 6 when operating the hydrodynamic coupling 4 and/or when switching on the hydrodynamic coupling 4 or when reducing the slip mentioned above.

The outlet 16 can include a return valve which prevents working medium from returning back to the working chamber 6 of the hydrodynamic coupling 4 via the outlet 16, as is indicated for instance in FIGS. 2, 5 and 6. Said return valve is however just an option.

The inlet 15 can be connected either to the pressure side 22 of the cooling medium pump 2 for conveying the working medium, see FIG. 1, wherein here said connection 13 for conveying the working medium can be interrupted by means of the valve 17, which is designed as a 2/2-way valve, optionally for the purposes mentioned above, or it can be connected to the space 8 filled with cooling medium of the compensating container 7, for conducting the working medium, whereas said connection can optionally be interrupted by a valve 18 for the purposes mentioned. According to the embodiment which is represented by FIG. 2, said valve 18 is also designed as a 2/2-way valve as disclosed in the embodiment according to FIG. 4. As can be seen, the air-conducting connection 10 and the connection 14 for conveying the working medium are run as a common pipe moreover according to FIG. 4, behind the region of the connection 14, for conveying the working medium in which the valve 18 is installed. To avoid the penetration of air in said commonly run part of the pipe, the valve 11 of the air-conducting connection 10 is arranged parallel to the valve 18 and before the mouth of the air-conducting connection 10 in the common pipe.

As shown, the inlet 15 is connected to the working chamber 6 via a connection 12 for conveying the working medium, to the suction side 21 of the cooling medium pump 2 according to FIGS. 3 and 6, whereas said connection 12 for conveying the working medium can optionally be interrupted by a valve 23. Although in this instance the valve 23 is designed as a common valve with the valve 11 in the air-conducting connection 10, two valves separated from each other can also be provided.

The outlet 16 of the working chamber 6 of the hydrodynamic coupling 4 can, as represented for instance in FIGS. 1, 5 and 6, and as indicated in FIG. 4 as a possible alternative by the dotted line, be connected via a connection for conveying the working medium, to the suction side 21 of the cooling medium pump 2. Consequently, said connection for conveying the working medium is also designated by the reference sign 12 in the Figures mentioned. The embodiment according to FIG. 6 thus shows two connection 12 for conveying working medium from the working chamber 6 to the suction side 21 of the cooling medium pump 2 and hence a connection of the inlet 15 to the outlet 16 via both said connections 12 for conveying the working medium.

In the embodiment according to FIG. 2, the inlet 15 is also connected to the outlet 16 of the working chamber 6. The connection provided accordingly for guiding the working medium from the outlet 16 and emerging upstream of the valve 18 in the connection 14 is designated by 24.

The mode of operation of the cooling systems represented in FIGS. 1 to 6 should now be described briefly below:

According to FIG. 1, the valve 17 between the inlet 15, leading to the working chamber 6, and the pressure side 22 of the cooling medium pump 2 in the connection 13 for conveying the working medium can optionally be opened and closed, in particular also be operated in a clocked manner so as to control and/or to regulate the inflow of working medium into the working chamber 6. In the circumstances under which the valve 17 interrupts the connection 13 for conveying the working medium, said working medium further flows out of the working chamber 6 via the outlet 16 in the direction of the suction side 21 of the working medium pump 2, whereas the corresponding volume in the working chamber 6 is replaced with air from the compensating container 7 which enables the working medium to flow out smoothly out of the working chamber 6 or the working chamber 6 to be emptied of the working medium smoothly. To avoid any undesirable by-pass flow of working medium from the working chamber 6 into the compensating container 7 via the air-conducting connection 10 during the operation of the hydrodynamic coupling 4, in particular when filling the working chamber 6 via the connection 13 for conveying the working medium, the valve 11, as already indicated, can be provided there and so be closed accordingly.

The embodiment according to FIG. 2 is similar to that of FIG. 1 in its function. The only difference here is the inflow of working medium into the hydrodynamic coupling 4 is carried out from the compensating container 7, see the connection 14 for conveying the working medium between the space 8 filled with cooling medium in the compensating container 7 and the inlet 15 leading to the working chamber 6. The valve 18 works accordingly like the valve 17 in FIG. 1. Another difference is moreover that the outlet 16 is connected to the connection 14 for conveying the working medium upstream of the valve 18 by means of the connection 24 for conveying the working medium and hence that working medium can flow from the outlet 16 to the inlet 15 via a bypass when valve 18 is open.

According to the embodiment in FIG. 3, the inlet 15 leading to the working chamber 6 is acted upon with air from the air chamber 9 or with working medium from the suction side 21 selectively by adjusting the switch position of the valve 11, 23. The valve 11, 23 can also be operated here in a clocked manner to control in an open or closed loop fashion the filling level of the working chamber.

According to FIG. 4, the valve 18 is either opened so as to supply working medium from the compensating container 7 to the inlet 15 leading to the working chamber, or the valve 11 is opened so as to supply air from the air chamber 9 to the inlet 15. The other valve is then closed accordingly.

The outlet 16 is connected to the compensating container 7, and more precisely in this instance to the air chamber 9, by means of the connection 25 for conveying the working medium. Alternately, a connection to the suction side 21 would also be possible, as indicated by the dotted line, or to the space 8 filled with working medium of the compensating container 7.

According to FIG. 5, the valve 11, 18 is toggled either to connect the air chamber 9 of the compensating container 7 to the inlet 15 leading to the working chamber 6 or to the space 8 of the compensating container 7, filled with working medium. Said valve can also, as the valves described previously, be operated in a clocked manner, if needed.

The embodiment according to FIG. 6 is similar to that of FIG. 5 in its function, with the exception that here it is not the working medium which is supplied from the compensating container 7, but rather from the suction side 21 of the working medium pump 2 accordingly to the inlet 15.

The actuation of the valves is particularly advantageously selected in the illustrated embodiments in such a way that in the case of failure of the control unit, the working chamber 6 of the hydrodynamic coupling 4 is filled with working fluid, so as to drive the cooling medium pump 2. 

1. Cooling system, in particular a motor vehicle cooling system, comprising a cooling circuit, in which a cooling medium is circulated by means of a cooling medium pump; wherein the cooling medium pump or another work machine is driven by means of a drive machine via a hydrodynamic coupling comprising a pump impeller driven by the drive machine and a turbine wheel driving the cooling medium pump, which together form a toroidal working chamber which can optionally be filled with working medium; wherein the working medium is the cooling medium; a compensating container, comprising a space filled with cooling medium and an air chamber above a cooling medium level in the space filled with cooling medium; characterised in that the working chamber of the hydrodynamic coupling is always connected to the air chamber or can optionally be connected to the latter via an air-conducting connection.
 2. Cooling system according to claim 1, characterised in that the cooling system is designed as a pressure-tight sealed system to the surrounding atmosphere, in particular with an overpressure with respect to the surrounding atmosphere.
 3. Cooling system according to claim 1, characterised in that a shut-off valve is provided in the air-conducting connection, in particular in the form of a directional valve, in order to interrupt and release the air-conducting connection selectively.
 4. Cooling system according to claim 1, characterised in that the working chamber of the hydrodynamic coupling is always connected to the suction side of the cooling medium pump or can optionally be connected to the latter via an additional connection for conveying the working medium.
 5. Cooling system according to claim 1, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the pressure side of the cooling medium pump via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 6. Cooling system according to claim 1, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 7. Cooling system according to claim 1, characterised in that the working chamber of the hydrodynamic coupling has an inlet and an outlet, whereas said inlet can be shut off, in particular by means of a valve, and the outlet is connected to the inlet via a connection for conveying the working medium, so that working medium discharged from the working chamber via the outlet is returned at least partially or completely back to the working chamber via the inlet.
 8. Cooling system according to claim 3, characterised in that the valve provided in the air-conducting connection and/or the valve provided in a connection for conveying the working medium, which is connected to the working chamber, can be operated in a clocked manner so as to adjust the filling level of the working chamber with working medium variably and including partial fill-ups.
 9. Cooling system according to claim 1, characterised in that the turbine wheel of the hydrodynamic coupling is designed integrally with a rotor of the cooling medium pump and/or carries the same, and is mounted in particular relatively on the pump impeller or on a shaft driving the same.
 10. Cooling system according to claim 2, characterised in that a shut-off valve is provided in the air-conducting connection, in particular in the form of a directional valve, in order to interrupt and release the air-conducting connection selectively.
 11. Cooling system according to claim 2, characterised in that the working chamber of the hydrodynamic coupling is always connected to the suction side of the cooling medium pump or can optionally be connected to the latter via an additional connection for conveying the working medium.
 12. Cooling system according to claim 3, characterised in that the working chamber of the hydrodynamic coupling is always connected to the suction side of the cooling medium pump or can optionally be connected to the latter via an additional connection for conveying the working medium.
 13. Cooling system according to claim 2, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the pressure side of the cooling medium pump via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 14. Cooling system according to claim 3 characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the pressure side of the cooling medium pump via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 15. Cooling system according to claim 4 characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the pressure side of the cooling medium pump via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 16. Cooling system according to claim 2, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 17. Cooling system according to claim 3, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 18. Cooling system according to claim 4, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 19. Cooling system according to claim 5, characterised in that the working chamber of the hydrodynamic coupling can optionally be connected to the space filled with cooling medium of the compensating container via an additional connection for conveying the working medium, whereas said connection can optionally be interrupted, in particular by means of a valve.
 20. Cooling system according to claim 2, characterised in that the working chamber of the hydrodynamic coupling has an inlet and an outlet, whereas said inlet can be shut off, in particular by means of a valve, and the outlet is connected to the inlet via a connection for conveying the working medium, so that working medium discharged from the working chamber via the outlet is returned at least partially or completely back to the working chamber via the inlet. 